I beg to differ. I have headlights on my car. When I turn them on during the daytime, they are self illuminated, but they will also reflect light from the sun that is much brighter than the lights themselves are normally. Plastic lights on a spaceship also would be expected to reflect specular light. If you don't want them to, then you can easily paint that bit out of the specular map.
Well, (un)fortunately 3D graphics and reality are two very different things. The way I described is how it works in 3dsmax (and in marks demo), and probably any major 3D package.